© Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 1 Topic 13 Forensic Toxicology Objectives After studying this topic you should:  be able to define "Forensic Toxicology"  be aware of the most common types of crime associated with toxic and pharmacologically active substances  understand the complementary roles of the forensic toxicologist and the forensic pathologist  be able to explain the role of the Coroner in investigation of suspicious deaths  be able to outline the procedure of an Autopsy in a suspected poisoning case  be able to explain the different types of sample collected and analysed by the forensic toxicologist, and  have a basic understanding of the interpretation of toxicological results in a forensic investigation. Autopsy Subject Source: Canadian Broadcasting Corporation. CBC: www.cbc.ca/quirks/ archives/03- 04/apr03.html Accessed 19-05-2007. Contents Introduction ............................................................................................................................ 1 13.1 The Incidence of Poisoning ........................................................................................... 3 13.2 The Forensic Toxicologist ............................................................................................. 5 13.3 The Forensic Process ................................................................................................... 5 13.4 The Autopsy .................................................................................................................. 6 13.5 Forensic Toxicology Samples ....................................................................................... 7 13.6 Analytical Procedures ................................................................................................... 9 13.7 Interpretation of Results .............................................................................................. 12 Postscript - The Ideal Poison .............................................................................................. 14 References .......................................................................................................................... 15 Introduction The American Board of Forensic Toxicology defines the subject as: "the study and practice of the application of toxicology to the purposes of the law." Reference: American Board of Forensic Toxicology http://www.abft.org/. Accessed 12-05-2007. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 2 It is this legal context that distinguishes forensic toxicology from other forms of toxicology. Forensic toxicologists generally investigate whether a toxic or pharmacologically active substance was involved in a crime or can provide evidence that can be used in a criminal investigation. Most commonly such crimes involve substances-of-abuse such as alcohol, cannabis or amphetamines. Most alcohol-related investigations involve drink-driving offences, while most other substance-of-abuse investigations are related to possession or trafficking of illicit drugs. An increasing number of forensic investigations involve performance-enhancing drugs in sport. Most poisoning cases turn out to be suicides or attempted suicide, or accidental overdoses; murder or attempted murder by poisoning is relatively rare. There are some forensic cases where poisoning is not the issue, but the presence of a substance in the body of a victim or suspect can provided evidence in the investigation. For example, a victim found dead in a burned-out building might have died as a result of the fire. In that case the lungs should contain smoke and the blood should contain considerable amounts of carbon monoxide. If these are absent then it could indicate that the victim died before the fire occurred. In this topic we will concentrate mainly on the forensic investigation of poisoning cases. It should be noted that similar approaches and techniques are used in other forensic investigations involving toxic or pharmacologically active substances. A few examples will help to illustrate these different types of forensic toxicology case: 1. Substances-of-abuse:  Illicit drugs such as methamphetamine, marijuana, barbiturates, opiates etc. In these cases the crime might be one of possession or trafficking.  Alcohol. While alcohol is not illegal, crimes involving alcohol can include driving while under the influence. 2. Substances affecting performance in sport:  Anabolic steroids or other substances used illegally by some athletes  Anabolic steroids or other substances used to enhance the performance of race horses or greyhounds or to "dope" them so that their performance is impaired (betting-related crimes) 3. Poisoning:  Intentional poisoning of another person - murder or attempted murder  Intentional self poisoning - suicide or attempted suicide  Accidental poisoning - for example overdoses of medicine and children drinking household cleaning agents (while these are not usually criminal acts they need to be investigated to rule out the possibility of criminal intent or culpability that might lead to a charge of manslaughter). 4. Substances as clues in criminal investigation:  The presence of a substance such as methamphetamine in the blood stream might indicate the state of mind of a person when a crime was committed  The absence of a vital medication, such as an antipsychotic drug, in someone might explain their criminal behaviour  The absence of carbon monoxide in the blood of a victim found in a burned-out building might indicate that they died before the fire occurred  The presence of a hypnotic substance such Rohypnol in the blood- stream of a victim might be a clue in a rape case. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 3 Key Concepts:  Forensic Toxicology is the study and practice of the application of toxicology to the purposes of the law.  This most commonly involves crimes associated with substances-of-abuse such as drugs and alcohol. It also covers substances affecting performance in sport, poisoning (suicide, accident and murder) and substances that can provide clues in other criminal investigations. Murder by poisoning is relatively uncommon. 13.1 The Incidence of Poisoning It has been reported that there are about 20,000 cases of hospitalisation for "self-harm" using poisons or drugs each year in Australia (Australian Network for Promotion, 2007). There are also thousands of overdoses due to the use of illicit drugs but these are not always reported. The number of deaths due to poisoning is probably only a few percent of the total poisoning cases. In the United States approximately 2 million cases of poisoning are reported each year and the number of poisoning deaths is about 700. Young children account for the majority of cases of poisoning, most of which are accidental, for example due to drinking household cleaners. The majority of fatal cases involve intentional poisoning of adults (mainly suicide). The number of murders or attempted murders by poisoning is probably less than a hundred each year on average. (Reference: http://faculty.ncwc.edu/toconnor/425/425lect14.htm accessed 10-05-2007). Table 1. The most frequently reported causes of poisonings (left) and the most frequently reported causes of deaths by poisoning (right): Most common causes of poisoning (USA) All poisoning Fatal poisoning 1 - Household cleaning supplies 1 - Antidepressant medications 2 - Analgesics (aspirin, acetaminophen) 2 - Analgesics (aspirin, acetaminophen) 3 - Cosmetics 3 - Street drugs 4 - Cough and cold remedies 4 - Cardiovascular drugs 5 - Plant scrapes and insect bites 5 - Alcohol 6 - Pesticides 6 - Gases and fumes 7 - Topical creams and lotions 7 - Asthma therapies 8 - Hydrocarbons (gasoline, kerosene) 8 - Industrial chemicals 9 - Antimicrobacterial soaps 9 - Pesticides 10 - Sedatives/hypnotics/antipsychotics 10 - Household cleaning supplies 11 - Food poisoning 11 - Anticonvulsant medications 12 - Alcohol 12 - Food, plants, and insects Reference: http://faculty.ncwc.edu/toconnor/425/425lect14.htm accessed 10-05-2007. Even though murder by poisoning is relatively uncommon, there have been some spectacular cases of serial and mass-poisoning such as the Shipman case in the UK (see case study below). There have also been some extortion attempts and attempted mass murders involving poisoning of food or medications, such as the Tylenol murders that killed 7 people in 1982 (http://en.wikipedia.org/wiki/Tylenol_scare) and the Sarin nerve gas attack in the Tokyo © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 4 subway that killed 12 and injured thousands in 1995 (http://news.bbc.co.uk/2/hi/asia- pacific/4365417.stm). Case Study 1: The Shipman Case (Extracts from BBC Archives from 2000 onwards) Britain's worst serial killer Harold Shipman was jailed four years ago for killing 15 of his women patients. But a public inquiry later decided the 57-year-old had killed at least 215 patients over 23 years. http://news.bbc.co.uk/2/hi/uk_news/3391895.stm By the time he was caught he was killing at a rate of one patient every ten days. http://news.bbc.co.uk/2/hi/uk_news/england/manchester/3392197.stm Serial killer Harold Shipman could have started murdering patients because he liked to experiment with drugs, says the final Shipman Inquiry report. Report author Dame Janet Smith said: "I think he was fascinated by drugs." "There is some evidence that he liked to 'test the boundaries' of certain forms of treatment," she said. "It is quite likely that some of the deaths Shipman caused resulted from experimentation with drugs." She said Shipman's own drug habit could have started while he was at PGI. It was also probable that his abuse of the drug pethidine - to which he later became addicted - could have started when he worked in the obstetrics unit, the report said. She said the way he tried to "ingratiate" himself with people in authority reminded her of the way he later ingratiated himself with Ghislaine Brant, manager of the pharmacy next to his surgery in Hyde, to get supplies of the drug diamorphine without question. An analysis showed Shipman signed an abnormally high number of death certificates between (6 pm) and midnight in hospital which could not be explained clinically. http://news.bbc.co.uk/2/hi/uk_news/england/manchester/4212627.stm Harold W Shipman What you should learn from this case study: You should be familiar with the name of Harold Shipman and that he almost got away with murdering about 215 people. The deaths were not investigated at the time as possible murders because they were mainly among the elderly who's deaths were not unexpected. He was only discovered after he tried to forge the will of one of his victims. This illustrates that poisoning can go undetected if it appear to be by "natural causes". Key Concepts:  Self-harm accounts for the majority of reported cases of poisoning.  Murder or attempted murder using poisons is relatively uncommon.  There are occurrences of mass murder by poisoning such as the Tylenol murders and the Shipman case.  If poisoning causes death with the appearance of natural causes it might go unnoticed. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 5 13.2 The Forensic Toxicologist The forensic toxicologist is usually someone who understands both analytical chemistry and toxicology. Forensic toxicologists usually work for the police, customs, coroners, or are private consultants who undertake medico-legal work. The work may include scene of crimes investigations, collecting evidence, keeping excellent documentation for chain of evidence purposes, consultation with pathologists, undertaking or overseeing the analysis of samples, interpreting the results, preparing reports, presenting evidence in court and acting as an expert witness. For further information about the work of a forensic toxicologist follow this link: http://www.sciencewa.net.au/science_careers.asp?pg=241 Key Concepts:  Forensic toxicologists are often analytical chemists who have some training in toxicology.  They do not carry out autopsies, but work with pathologists to help solve crimes involving toxic or pharmacologically active substances. 13.3 The Forensic Process When a person is found deceased in suspicious circumstances, the death might be investigated by the police or by the State Coroner. In Victoria, the Coroner’s Office is co- located with the Victorian Institute of Forensic Medicine (VIFM). If there is evidence at the time of the discovery of the body that the death was the result of, or linked with, a crime then police investigations will commence and proceed alongside the Coroner's investigation. The Coroner's role is to determine the identity of the deceased and the circumstances and cause of death. The Coroner decides whether an autopsy (post mortem examination) needs to be performed. Autopsies are carried out by a pathologist of the Coroner's office or a specialised forensic pathologist of the VIFM if a crime is suspected. The Coroner inquires into the circumstances of the death and the medical history of the deceased. If the death appears to be by natural causes and a crime is not suspected, then the Coroner's report closes the case. If other investigations are required then the Coroner will order an inquest. If a crime is later suspected then the case will be referred to the Director of Public Prosecutions and possibly then become a matter for the police. Key Concepts:  Deaths in suspicious circumstances are investigated by the State Coroner 's Office.  Autopsies are carried out by pathologists.  In Victoria, when a criminal death is suspected an autopsy might be carried out by a pathologist of the Victorian Institute of Forensic Medicine (VIFM). © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 6 13.4 The Autopsy The pathologist will first review the medical records of the victim, if available, and information about the circumstances of the death. These might provide clues as to the cause of death. The next steps include the collection of trace evidence from the surface of the body and clothing and removal of clothing and personal items. There will then be a external examination of the skin, eyes, ears, nose and mouth. The next steps involve a detailed internal examination in which the body is opened up surgically and organs removed and inspected. Body fluids and tissue samples are collected for chemical analysis for drugs or poisons. This can be a complex process and may take many weeks to complete, unlike on certain forensic TV shows where the results appear within minutes or hours. Evidence collected from the scene of crime, home or place of work of the victim, such as food, drink, pills and empty containers may also be examined for traces of drugs or poison. The pathologist might find evidence of poisoning even before any poison is detected in the person's body. The post mortem examination might reveal certain pathological changes consistent with specific poisons, for example bright red skin and blood possibly indicates carbon monoxide poisoning (Table 2). Table 2 - pathological observations that suggest possible poisoning. Pathological observation Possible cause Burns around mouth, lips, nose Acids Skin of face and neck quite dark Aniline, nitrobenzene Severe, unexplained diarrhoea Metals (arsenic, mercury, copper, etc.) Pupil of eye dilated Atropine (Belladonna), Scopolamine Burns around mouth, lips, nose Bases (lye, potash, hydroxides) Odour of disinfectant Carbolic acid or other phenol Skin is bright cherry red Carbon monoxide Quick death, red skin, odour of peach Cyanide Vomiting, abdominal pain Food poisoning Diarrhoea, vomiting, abdominal pain Metallic compounds Convulsion Nicotine Pupil of eye contracted Opiates Odour of garlic Oxalic acid, phosphorous Convulsion Sodium fluoride Convulsion, dark face and neck Strychnine Source: Modified from http://faculty.ncwc.edu/toconnor/425/425lect14.htm Victim still alive? If a poisoning victim is still alive then the first objective is to treat the person as a hospital patient and try to ensure recovery. If a crime is suspected then the police will want to interview the patient and other witnesses and forensic toxicologists will carry out an investigation of the poisoning including the collection of biological fluids for chemical analysis. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 7 Key Concepts:  An autopsy involves: o a review of the medical records of the victim, if available, and information about the circumstances of the death o the collection of trace evidence from the surface of the body and clothing o an external examination of the skin, eyes, ears, nose and mouth o a detailed internal examination in which the body is opened up surgically and organs removed and inspected o collection of body fluids and tissue samples for chemical analysis for drugs or poisons.  The autopsy might reveal pathological changes consistent with specific poisons even before any poison is detected in the person's body.  If a poisoning victim is still alive then the first objective is to ensure recovery. If a criminal poisoning is suspected then a forensic investigation may proceed during the treatment period. 13.5 Forensic Toxicology Samples Forensic toxicology samples may be obtained from crime scenes, accident scenes, hospital emergency departments, post mortem examinations, goods confiscated by the customs, sports drugs testing, horse race doping incidents etc. These samples may be either biological or non-biological. Biological samples include:  blood,  urine,  hair,  nails,  saliva,  tissues and  exhaled breath Non-biological samples include:  unidentified pills,  powders,  liquids, and  gases. If a person was suspected of being poisoned by substance added to his drink or food then the following samples might be taken:  samples of the stomach contents, blood and tissues  samples of the food and drink from the crime scene  samples of any substances found at the crime scene or other relevant locations such as the victims home and place of work These forensic investigations would be carried out in parallel to normal police inquiries. Like all forensic evidence, toxicology samples must be handled and documented by the forensic science laboratory in a manner that will preserve the "chain of evidence" (also known as the chain of custody) otherwise the evidence may become invalid in court. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 8 Non-biological samples may be important in a forensic investigation. For example, unidentified pills may be confiscated in an arrest and need to be analysed. Suspicious substances might also be found at the scene of an attempted or actual suicide, or accidental poisoning. A "clandestine" laboratory that is suspected of manufacturing illicit drugs might be discovered by the police and it may be necessary to analyse the raw materials and traces of product to see if they are illegal substances. Biological samples may be collected from living subjects (for example someone suspected of driving under the influence of drugs) or deceased subjects who may have died of a drug overdose or poisoning. When the subject is still living, biological samples may be taken in the form of blood, urine, saliva, or exhaled breath. Blood samples are suitable for most substances that can be absorbed into the body. Urine samples are suitable only for those substances that are excreted in their original form, or as known metabolites, in urine. Exhaled breath is suitable for volatile substances such as alcohol, carbon monoxide and solvents (some of which are commonly abused by "glue sniffers" or "petrol sniffers"). When the subject is deceased a wider range of sample may be taken including tissue samples. The concentration of some substances continues to change in some body fluids and tissues after death. This means that care must be taken in collecting and preserving biological samples. Decomposition and bacterial action can further change the composition of biological samples and it is necessary to preserve them, for example by adding sodium fluoride as a preservative. Where the body has undergone substantial decomposition or dehydration it may not be possible to obtain a blood sample and samples of organ tissue may have to be used instead. In some cases the vitreous humour of the eyes may be the most suitable medium. Table 3 - Typical samples for toxicological analysis Type Quantity Analysis Blood (heart, femoral) 20 ml Volatiles, drugs Urine 20 ml Drugs, heavy metals Bile 20 ml Narcotics, other drugs Kidney Entire In absence of urine Liver 20 g Many drugs Gastric contents Total Drugs taken orally Vitreous humor Both eyes Alcohol, glucose, drugs and electrolytes Reference: Modified from R C Backer, in: General and Applied Toxicology, Ballantyne, Marrs and Turner, Abridged edition, McMillan Press 1995, pp 1077 - 1095. When a post mortem blood sample is required, it is common to take the sample from the heart. However, the concentration of some drugs in the blood in the heart may change significantly after death so it is now increasingly common for blood samples to be taken from the femoral artery in cases of suspected drug overdose. Drugs shown to have significant anatomical site concentration changes after death include amphetamine, methamphetamine, caffeine, pethidine and cocaine. Blood alcohol concentration may change dramatically post mortem, particularly if bacterial or fungal infection occurs leading to fermentation of body sugars into alcohol. It is possible for high concentrations of alcohol to be found in a cadaver even when there was non present at the time of death. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 9 Key Concepts:  Forensic toxicology samples may be biological or non-biological.  Biological samples are usually obtained from victims and can include samples of the stomach contents, blood and tissues.  Non-biological samples include samples of the food and drink, unidentified pills, powders, liquids, and gases and empty containers.  The concentration of toxic substances in the body change continuously after administration and continue to change in some body fluids and tissues after death.  Decomposition and bacterial action can further change the composition of biological samples.  Where the body has undergone substantial decomposition or dehydration, tissue such as the vitreous humour of the eyes may still contain the substance for some time.  Forensic toxicology samples must be handled and documented in a manner that will preserve the "chain of evidence" otherwise the evidence may become invalid in court. 13.6 Analytical Procedures The problem faced in many forensic toxicology investigations is deciding what substances to look for. There are thousands of possible substances that could be encountered in poisoning or drug overdose cases and millions of possible substances that could be found in non- biological samples. There are techniques for the analysis of almost all of these, but without a short-list of possible agents it would be a very difficult task to decide what to look for and what technique to use. There are three approaches to help overcome this problem.  The first approach is to examine the situation that led up to the poisoning and try to make an intelligent informed guess about what substances might be involved. For example, if a suspected suicide case is found in a home and there are various pill bottles in the vicinity then this suggests what substances might be involved and should be looked for by the forensic toxicologist in the biological samples.  The second is to consider the clinical signs that might indicate the type of poison that was involved.  The third method is to start with so-called "screening tests" that indicate (but do not prove) the presence of certain types of substance. These approaches can often lead to a short-list of substances that the analytical toxicologist can look for. Without this short-list the analyst's job is very difficult. If the pathologist strongly suspects that someone was poisoned and yet it is not possible to develop a short-list then the analyst is faced with analysing for "general unknowns". The analysis of general unknowns requires a large battery of expensive analytical screening techniques and is not guaranteed to provide positive results. The techniques used include liquid chromatography, gas chromatography and mass spectrometry. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 10 Key Concepts:  The problem faced in many forensic toxicology investigations is deciding what substances to look for.  Without a short-list of possible agents it would be a very difficult task to decide what to look for and what technique to use.  There are three approaches to help overcome this problem: o examine the situation that lead up to the incident and try to make an intelligent informed guess about what substances might be involved o consider the clinical signs that might indicate the type of poison that was involved o start with so-called "screening tests" that indicate (but do not prove) the presence of certain types of substance.  Without a short-list the analyst is faced with analysing for "general unknowns". This requires a large battery of expensive analytical screening techniques and is not guaranteed to provide positive results.  It is not necessary to understand the analytical techniques used in forensic toxicology for the study of SBC312. 13.6.1 Screening tests These tests are rapid and relatively cheap and indicate the possible presence of certain types of compound in biological samples, and can sometimes be used for non-biological samples. Screening tests sometimes use colorimetric reagents that change colour in the presence of certain substances. A typical multiple drug screening kit. ProScreen. Australian Drug Testing. http://www.australiadrugtesting.com/ Screening test kits are available commercially for a variety of types of substance including aspirin, paracetamol, substances-of-abuse, heavy metals and many other groups of compound. The test results are not conclusive and are said to be "presumptive". If a positive result is found then further more reliable (usually slower and more expensive) methods must then be applied to confirm the results and identify the specific compounds involved. The specific method of analysis that is applied depends to a large extent on the characteristics of the suspected compounds. Broad classes of compound referred to in forensic toxicology are listed in table 4. Table 4. Broad classes of substances frequently found in post mortem investigations. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 11 A. Gases and volatiles B. Acids C. Neutrals D. Bases E. Metals Alcohols, chlorinated hydrocarbons, aromatic hydrocarbons, carbon monoxide, cyanide Barbiturates, salicylates, paracetamol (acetaminophen) Glutethimide, ethchlorvynol, meprobamate, carisoprodol Cocaine, propoxyphene, opium alkaloids, antidepressants, benzodiazepines Arsenic, mercury, thallium, lead 13.6.2 Separation of Substances from Biological Fluids Before a biological sample can be analysed to see if it contains poisons or substances-of- abuse it is usually necessary to separate the substances from the biological fluid or tissue. Obviously it is not possible to introduce a piece of liver into an analytical instrument such as a chromatograph. The same applies to blood and urine and other biological fluids. They are so complex and contain so many dissolved or suspended solids that they would block the instrument as well as interfering with the analytical results. The methods used to extract the substances of interest depend on their chemical and physical properties. Volatile compounds can be extracted by vaporisation, either directly or be steam distillation. The sample is placed in a flask and a stream of steam is passed through it. The volatile substances evaporate and are carried by the steam into a condenser where they are cooled and collected as a liquid condensate which can then be collected for analysis. Steam distillation can be used to strip volatile compounds out of blood, urine or macerated tissue, such as alcohol, phenols, hydrocarbons, substituted hydrocarbons (such as carbon tetrachloride), cyanide and certain volatile basic drugs such as amphetamines, methadone and nicotine. Head space extraction can also be used for volatile compounds. The sample is placed in a small bottle which is held at a steady temperature allowing the volatile substance to evaporate into the space in the bottle above the sample (head space). A sample of the vapour in the head space is then taken and injected into the analytical instrument (most commonly a gas chromatograph). Solvent extraction can be used to remove compounds from biological specimens according to their solubility. A solvent is used that will dissolve the compounds of interest and leave much of the biological material undissolved. 13.6.3 Analytical Methods A wide range of analytical methods are used in forensic toxicology for the identification of toxic and pharmacological substances. These include, colorimetric tests, Radio-Immuno- Assay, gas chromatography, liquid chromatography and mass spectrometry. Some of the more common analytical techniques used in forensic toxicology are listed in Table 5. Table 5 - Some of the more common analytical techniques used in forensic toxicology. Type of Compound Analytical Method Reference Gases and Volatile Compounds Simple mixtures, known compounds Gas Chromatography (GC) http://en.wikipedia.org /wiki/Gas_chromatography " Complex Gas http://en.wikipedia.org/wiki/ © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 12 mixtures, unknown compounds Chromatography / Mass Spectrometry (GC/MS) Gas_chromatography-mass_spectrometry Non-volatile organic compounds Simple mixtures, known compounds High Performance Liquid Chromatography (HPLC) http://en.wikipedia.org/wiki/ Liquid_Chromatography# High_performance_liquid_chromatography _.28HPLC.29 " Complex mixtures, unknown compounds Liquid Chromatography / Mass Spectrometry (LC/MS) http://en.wikipedia.org/wiki/ Liquid_chromatography- mass_spectrometry Toxic Metals Atomic Absorption Spectrometry (AAS) http://en.wikipedia.org/wiki/ Atomic_absorption_spectroscopy 13.7 Interpretation of Results Once the analytical results have been obtained they must be correctly interpreted. If the analysis went well then the forensic toxicologist and pathologist should know what toxic substances were present in the body and in any samples collected form the crime scene or other relevant locations. In investigating a possible fatal poisoning the first question that may be considered in interpreting the results of the analysis is: was there poison present in the body in sufficient amounts to have caused the death in the manner observed? This can be estimated from the body burden (dose) and the LD50 of the poison. Lets say that the amount of a particular poison in the body was estimated to be 300 mg and the LD50 was 20 mg/kg (which for a 70 kg person is equivalent to a dose of about 1,400 mg) then it is unlikely that the poison could have been the direct cause of death. It should be noted that the poison that is still in the stomach of a deceased person is not actually part of the body burden. If the dose is found to be insufficient to have directly caused death it might still have been sufficient to have caused some other effects and perhaps contributed to the death, for example by precipitating a heart attack. Alternatively it might have had an incapacitating effect which then allowed other events to occur, for example it might have caused unconsciousness, during which time the victim choked or was suffocated. The disposition (location) of the poison in the body can often provide evidence about the time and duration of the poisoning. The presence of a significant amount of poison in the stomach indicates that it was administered recently. If a fat-soluble poison is found in the stomach and bloodstream but not in the fat in very large amounts it might rule out the possibility that the poisoning occurred over a period of days or weeks (otherwise it would have accumulated in the fatty tissue of the body). Some poisons, particularly toxic metals such as lead, are known to accumulate in bone over along period. If a deceased person has very large amounts of lead in their bloodstream and soft tissues but not in bone it indicates that they were poisoned recently. If the concentration is very high in bone it indicates that they were poisoned over a long period. A similar effect can be seen with poisons that accumulate in hair, such as arsenic and thallium. The hair contains a record of the dose of these poisons received by a person over a long period. The case study below involves poisoning by thallium. The hair analysis segment- by-segment provided a twelve-month record of repeated poisoning and showed a massive increase shortly before death. Another use of hair analysis is for drugs that are likely to have © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 13 disappeared quickly from other compartments of the body. An example is provided by the date-rape drug Rohypnol (http://faculty.washington.edu/chudler/roof.html) Rohypnol and its major metabolite 7-aminoflunitrazepam can be detected in urine for 5 days or so after administration of a single dose of Rohypnol. The metabolites of Rohypnol (but not Rohypnol itself) accumulate in hair and can be detected in that medium at least a month after the drug has been administered (Negrusz A., 2001). Case Study 2 http://www.crimelibrary.com/criminal_mind/forensics/cyril_wecht/7.html Robert Curley, 32, began to grow ill in August 1991, entering the hospital in Wilkes-Barre, Pennsylvania, for a series of tests before he finally died in September. His doctors went through several diagnoses for his burning skin, numbness, weakness, repeated vomiting and rapid hair loss. Just before he died, he became more agitated and aggressive, so he was transferred to a hospital that could test for heavy metal exposure. Sure enough, he had elevated levels of thallium in his system-a substance used in rat poison before being banned in 1984. A search of his worksite turned up bottles of thallium salts for a chemistry lab, but none of his co-workers had experienced symptoms. The levels measured in Curley at autopsy were so high it was clear that he'd been deliberately poisoned, and his death was ruled a homicide. As Cyril Wecht describes it in Mortal Evidence, his brain had swelled so much it had pushed down into the spinal column. Suspicion turned to the home, and it was determined that Curley's wife and stepdaughter also had elevated levels of thallium in their systems, but not to toxic levels. Yet investigators found only a tea thermos that showed traces of the poison. At a dead end, authorities approached Dr. Frederic Rieders of National Medical Services, a private toxicology lab in Willow Grove with extensive testing abilities, to do a more thorough analysis of the tissues. Rieders requested more samples, so Joann Curley agreed to have her husband exhumed. Hair shafts were removed, along with toenails, fingernails, and skin samples. Dr. Rieders conducted a segmental analysis on the hair shafts to devise a timeline of thallium exposure and ingestion. The hair strands from Curley's head were sufficiently long to plot almost a year of his life prior to his death. Concentrations of thallium were measured over the course of nine months, with spikes and drops that suggested a systematic ingestion long before Curley had begun his job at the university. Clearly, that was not where he had first received his exposure to thallium. There was also a massive spike just a few days before his death that suggested intentional poisoning. At that time, his family had brought in some food and his wife had been alone with him. The culprit seemed clear and Joann Curley was charged. The prosecution prepared for trial, calling in some big-hitters. "I was an expert, with Michael Baden and Fred Rieders, for the DA," says Wecht. "I was the only one to testify at the preliminary hearing and I went through the entire forensic pathology and toxicology stuff that the three of us had prepared. It was a beautiful case because it had to do with the sequential chronological testing of a hair from its follicle to its tip. It showed the peaks and valleys of his poisoning. When he was away, he had a valley and when he was home or with his wife, he had a peak." His role, he points out, was to interpret the toxicological findings in terms of cause of death. "The forensic toxicologist can come up with the technical methodology and findings, but the pathologist is needed to talk about cause of death and relate it to the science and symptoms and critical episodes. It's a joint effort." In a plea deal, Joann Curley confessed to using rat poison to enrich herself on her husband's life insurance payment. She received a sentence of 10 to 20 years in prison. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 14 What you should learn from this case study: You shouldn't try to remember the details of this case but you should note that this provides an example of the use of hair analysis to determine that poisoning occurred over an extended period and provide information about the time-sequence. These are a few examples of a complicated area of forensic science. The correct interpretation of the distribution of a particular poison in the body requires some understanding of the toxicokinetics of the substance. Nevertheless, forensic toxicology can often reveal not only that a person has been poisoned and with what, but also the time- sequence of the poisoning. Key Concepts:  Once the analytical results have been obtained they must be correctly interpreted. o Was there poison present in the body in sufficient amounts to have caused the death? o If the dose was insufficient to have directly caused death was it sufficient to have caused some other effects and perhaps contributed to the death, or caused some other effect such as intoxication of incapacitation? o Are the pathological changes consistent with poisoning by that substance? o Does the disposition (location) of the poison in the body indicate recent or cumulative poisoning?  The disposition of the poison in the body can often provide evidence about the time and duration of the poisoning:  The presence of a significant amount of poison in the stomach indicates that it was administered recently.  Administration of a poison over a short period before death might result in the poison getting into the blood stream and organs but not into hair and bones and possibly not much into fat.  Administration of a poison over a long period might result in the poison accumulating in storage sites including the fat, bones and hair.  The hair can contain a record of the dose of poisons received over a long period. Postscript - The Ideal Poison Crime fiction writers often write about the ideal poison - the poison that is perfectly effective and undetectable. There is good evidence that the intelligence services in some former Soviet Union countries put a great deal of effort into finding the ideal poison for assassination purposes. Bulgarian dissident Georgi Markov was killed by poison dart filled with ricin (Anon. Georgi Markov, "The Umbrella Assassination" http://www.portfolio.mvm.ed.ac.uk/studentwebs/session2/ group12/georgie.htm. Accessed 08-05-07.) and former Russian spy Alexander Litvinenko was killed with radioactive Polonium-210 (Anon. Alexander Litvinenko. http://en.wikipedia.org/wiki/Alexander_Litvinenko. Accessed 01-04-2007). Forensic toxicologists are interested in ideal poisons from a crime detection perspective. If a perfect poison existed what characteristics would it have and could it be detected? The ideal poison could be a liquid, solid or gas. It would presumably be one that killed effectively and allowed the perpetrator to avoid suspicion. Author: Publisher: Scholastic Inc. ISBN-10: 0545092310. Book Description:Follow the steps toxicologists take when examining bodies and crime scenes for traces of poison. Analyze bones as forensic anthropologists identify victims. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 15 The following characteristics might define the ideal poison:  it would be very toxic so that a relatively small dose would cause death  it would have no taste or smell so that the victim did not notice that he was taking it  it would be easy to administer, for example in a drink, food, medication or in air (if a gas)  it would be difficult to detect in the body or in non-biological samples (it might be difficult to analyse, or it might be excreted rapidly or converted into something else)  it would cause death in a way that looked like natural causes or an accident (e.g. an overdose or occupational exposure)  it would have a delayed effect so that the perpetrator could get away, and yet it would act quickly once symptoms started so that there would be no time to identify and treat the poisoning  it should be readily obtainable otherwise its source could be traced if it was identified. Are there any ideal poisons with all of these characteristics? Probably not; but there are many that have a number of these. There is probably a large and unknown number of unidentified poisonings (such as in the Shipman case) that probably rely on death appearing to be by natural causes, but when the death involves a younger healthy person with no known medical history then suspicions are always aroused. The Markov and Litvinenko cases illustrate that when the suspicions of the authorities in Western countries are aroused the poison is likely to be identified. References American Board of Forensic Toxicology http://www.abft.org/. Accessed 12-05-2007. Anon. Alexander Litvinenko. http://en.wikipedia.org/wiki/Alexander_Litvinenko. Accessed 01- 04-2007. Anon. Atomic_absorption spectroscopy http://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy. Accessed 01-04-2006. Anon. Drug Testing Kits, ProScreen. Australian Drug Testing. http://www.australiadrugtesting.com/. Accessed 12-05-07. Anon. Forensic Toxicology. http://faculty.ncwc.edu/toconnor/425/425lect14.htm Accessed 10- 05-2007. Anon. Gas chromatography-mass spectrometry http://en.wikipedia.org/wiki/Gas_chromatography-mass_spectrometry. Accessed 01-04-2006. Anon. Georgi Markov, "The Umbrella Assassination" http://www.portfolio.mvm.ed.ac.uk/studentwebs/session2/group12/georgie.htm. Accessed 08- 05-07. Anon. High performance liquid chromatography http://en.wikipedia.org/wiki/Liquid_Chromatography #High_performance_liquid_chromatography_.28HPLC.29. Accessed 01-04-2006 Anon. Liquid chromatography-mass spectrometry http://en.wikipedia.org/wiki/Liquid_chromatography-mass_spectrometry. Accessed 01-04- 2006. Anon. Meet Robert Hansson, Forensic Toxicologist. Science Network, Western Australia. http://www.sciencewa.net.au/science_careers.asp?pg=241. Accessed 12-05-07. © Deakin University SLE312 Toxicology TOPIC 13 FORENSIC TOXICOLOGY 16 Anon.Gas chromatography http://en.wikipedia.org/wiki/Gas_chromatography. Accessed 01- 04-2006. Australian Network for Promotion, Prevention and Early Intervention for Mental Health (www.auseinet.com), March 2007. Accessed 18-05-2007. Backer, R.C., in: General and Applied Toxicology, Ballantyne, Marrs and Turner, Abridged edition, McMillan Press 1995, pp 1077 - 1095. BBC. Sarin Nerve Gas Attack in 1995. http://news.bbc.co.uk/2/hi/asia-pacific/4365417.stm. Accessed 12-05-07. BBC. The Shipman Case: http://news.bbc.co.uk/2/hi/uk_news/3391895.stm, http://news.bbc.co.uk/2/hi/uk_news/england/manchester/3392197.stm http://news.bbc.co.uk/2/hi/uk_news/england/manchester/4212627.stm. Accessed 12-05-07. Canadian Broadcasting Corporation. CBC: www.cbc.ca/quirks/ archives/03-04/apr03.html. Accessed 19-05-2007. Negrusz A., Detection of "Date-Rape" Drugs in Hair and Urine, Final Report, NCJ 201894, National Institute of Justice/NCJRS, Paper Reproduction Sales, Box 6000 Department F, Rockville, MD 20849, United States, 2001. http://www.ncjrs.gov/pdffiles1/nij/grants/201894.pdf Accessed 12/05/2007. Wecht, C., Pennsylvania Mystery, Courtroom Television Network LLC. http://www.crimelibrary.com/criminal_mind/forensics/cyril_wecht/7.html. Accessed 05-05-07. Wikipedia, The Tylenol Scare. http://en.wikipedia.org/wiki/Tylenol_scare. Accessed 12-05-07. End of Topic